SPC AC 051952

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0252 PM CDT SUN APR 05 2015

   VALID 052000Z - 061200Z

   ...THERE IS A MRGL RISK OF SVR TSTMS OVER PARTS OF SW TX...

   ...THERE IS A MRGL RISK OF SVR TSTMS A SMALL PART OF SE TX...

   ...SUMMARY...
   THUNDERSTORMS WILL BE POSSIBLE THROUGH TONIGHT ACROSS PARTS OF 
   TEXAS...OKLAHOMA...THE OZARKS...AND THE LOWER MISSISSIPPI
   VALLEY...AND FROM THE PACIFIC NORTHWEST INTO THE NORTHERN ROCKIES. A
   FEW STORMS WITH HAIL MAY OCCUR OVER SOUTHWEST TEXAS LATE THIS
   AFTERNOON.

   ...SOUTHWEST TX...
   ISOLATED THUNDERSTORMS APPEAR LIKELY TO DEVELOP THIS
   AFTERNOON...PRIMARILY OVER THE HIGHER TERRAIN OF SOUTHWEST TX. A
   WELL-MIXED BOUNDARY LAYER AND SFC DEWPOINTS NEAR 50 F COMBINED WITH
   40-50 KTS OF MIDLEVEL FLOW COULD SUPPORT A THREAT FOR LARGE HAIL
   WITH ANY DISCRETE STORMS THAT DEVELOP. LATEST CAMS GUIDANCE ALSO
   SHOWS THE POTENTIAL FOR STORMS DEVELOPING FARTHER UPSTREAM ACROSS NW
   MX TO MOVE ACROSS THE BIG BEND AREA LATER THIS EVENING...WHICH COULD
   ALSO POSE A THREAT FOR HAIL WITH STEEP MIDLEVEL LAPSE RATES AND
   MODERATE CLOUD-LAYER SHEAR PERSISTING.  

   ...SOUTHEAST TX...
   MARITIME AIR CONTINUES TO SLOWLY ADVANCE NWD ACROSS THE TX COASTAL
   PLAIN...BUT WIDESPREAD CLOUD COVER PERSISTS ACROSS MUCH OF EAST TX N
   OF THE MARINE BOUNDARY. MODEST DESTABILIZATION IS OCCURRING S OF THE
   FRONT AS TEMPERATURES ARE WARMING INTO THE LOW 70S F...AND WILL
   CONTINUE TO SUPPORT THE POTENTIAL FOR STRONGER UPDRAFTS THIS
   AFTERNOON. THE RISK FOR A WEAK TORNADO OR TWO WILL EXIST THROUGH THE
   EARLY EVENING...GIVEN A STORM DEVELOPING/PROGRESSING ALONG THE
   MARINE BOUNDARY.

   ..ROGERS.. 04/05/2015

   .PREV DISCUSSION... /ISSUED 1129 AM CDT SUN APR 05 2015/

   ...SYNOPTIC SETUP...
   ZONAL FLOW WILL PERSIST ACROSS MUCH OF THE NATION DOWNSTREAM FROM
   CLOSED LOW OFF THE WA-ORE CST...AND N OF FLAT RIDGE OVER THE GULF OF
   MEXICO. LEAD IMPULSE ASSOCIATED WITH THE OFFSHORE LOW...NOW
   APPROACHING SW ORE-NRN CA...WILL CONTINUE E/NE INTO ID EARLY MON.
   FARTHER S...SRN STREAM DISTURBANCE NOW OVER NM SHOULD REACH OK THIS
   EVE...WITH MINIMAL IMPACT OVER CNTRL AND S TX.  

   LEE TROUGH WILL STRENGTHEN OVER THE CNTRL AND SRN HIGH PLNS THROUGH
   MON AS COOL SFC RIDGE NOW DOMINATING THE LWR MS VLY AND SOUTHEAST
   CONTINUES E INTO THE ATLANTIC.
    
   ...SW TX THIS AFTN/EVE...
   LOW-LVL MOISTURE THAT SPREAD NWWD INTO MUCH OF TX YESTERDAY WILL
   REMAIN IN PLACE TODAY AS 850 MB FLOW REMAINS NEARLY SLY IN RESPONSE
   TO STRENGTHENING OF HIGH PLNS LEE TROUGH. ASCENT ATOP
   RESIDUAL...SHALLOW COOL-AIR LAYER LIKELY WILL MAINTAIN THICK CLOUD
   COVER OF MUCH OF CNTRL AND S TX TODAY. HOWEVER...ALONG THE WRN EDGE
   OF THE CLOUDS OVER SW TX...FAIRLY STRONG SFC HEATING SHOULD
   OCCUR...WITH SATELLITE SUGGESTING ONLY A LIMITED AMOUNT OF
   SRN-STREAM-RELATED HIGH CLOUDINESS. AT THE SAME TIME...SLIGHTLY
   ENHANCED /40-50 KT/ 500 MB FLOW ASSOCIATED WITH PASSING NM UPR
   IMPULSE WILL MAINTAIN SUBSTANTIAL WSWLY DEEP SHEAR OVER REGION.

   THE STRONGEST FORCING FOR ASCENT WILL PASS N OF THE BIG BEND...AND
   WILL OCCUR FAIRLY EARLY IN THE DIURNAL CYCLE. BUT COMBINATION OF SFC
   HEATING AND TERRAIN CIRCULATIONS SHOULD FOSTER SCTD LATE AFTN STORMS
   OVER THE DAVIS MTNS EWD TO THE TRANS-PECOS REGION. STEEP MID-LVL
   LAPSE RATES...PW AOA 1.00...AND THE LIKELIHOOD FOR DISCRETE UPDRAFTS
   COULD YIELD A FEW STORMS WITH SVR HAIL. THE CONVECTION SHOULD WEAKEN
   FAIRLY RAPIDLY AFTER SUNSET GIVEN DECREASING BUOYANCY AND FORCING
   FOR ASCENT. 
     
   ...SE TX THIS AFTN...
   SATELLITE AND SFC OBSERVATIONS ATTM SHOW LEADING EDGE OF SFC-BASED
   MARITIME TROPICAL AIR JUST ENTERING THE MIDDLE TX GULF CST ATTM AS
   LOW-LVL WAA/MOISTURE TRANSPORT CONTINUE ALONG SW FRINGE OF
   RETREATING COOL AIR DOME ASSOCIATED WITH SERN STATES SFC RIDGE.
   CURRENT STREAM LINE AND PRES CHANGE DATA SUGGEST THAT A WEAK WARM
   FRONT MAY BE IN THE PROCESS OF FORMING FROM N OF VCT TO N OF HOU TO
   NEAR BPT. THIS FEATURE SHOULD DRIFT SLOWLY NWD THROUGH LATER
   TODAY....BEFORE BECOMING MORE DIFFUSE AS SLY FLOW OVER E TX
   STRENGTHENS EARLY MON.

   SFC HEATING WILL BE WEAK AND LARGE-SCALE FORCING FOR ASCENT MINIMAL.
   BUT SHALLOW CONVERGENCE/UPLIFT WILL EXIST ALONG THE BOUNDARY...AS
   WILL RICH MOISTURE /PW AOA 1.50 INCHES/. AND...WIND PROFILES WILL
   FEATURE 40+ KT WLY DEEP SHEAR WITH A SIZABLE LOW-LVL DIRECTIONAL
   COMPONENT...ESPECIALLY NEAR FRONT. GIVEN THIS SETUP...A CONDITIONAL
   RISK WILL EXIST FOR A STORM OR TWO WITH LOW-LVL ROTATION AND A
   NON-ZERO TORNADO THREAT.

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